Immune remodeling via mitochondria-dependent STING activation enhances cabozantinib response in hepatocellular carcinoma.

BACKGROUND: Cabozantinib, a tyrosine kinase inhibitor (TKI) approved for advanced hepatocellular carcinoma (HCC), has established clinical benefit although the underlying immunomodulatory mechanisms, particularly those involving mitochondrial stress and the cGAS/STING pathway, remain poorly defined. METHODS: We assessed cabozantinib’s effects on mitochondrial integrity and innate immune signaling in hepatoma cells and macrophage cell lines, analyzing mitochondrial depolarization, reactive oxygen species production, cytosolic release of mitochondrial DNA (mtDNA), activation of the cGAS/STING pathway and induction of type I interferon-stimulated genes (ISGs). Functional relevance was tested by mtDNA depletion and CRISPR-mediated STING knockdown. The in vivo effects of cabozantinib and the STING agonist DMXAA were examined in immunocompetent mouse models. Translational relevance was evaluated by multiplex proteomic profiling of serum samples from 18 cabozantinib-treated HCC patients across two independent cohorts. RESULTS: Cabozantinib induced mitochondrial depolarization, oxidative stress, and cytosolic mtDNA release, resulting in STING-dependent signaling and ISG upregulation in hepatoma cells. Disruption of mtDNA or STING abrogated these effects. In vivo, cabozantinib reduced tumor growth and promoted tumor-infiltrating lymphocyte activation, which were further enhanced by DMXAA co-treatment. Patient serum proteomics revealed consistent increases in immune and stress-related proteins (e.g., granzyme B, HO-1, CAIX, CXCL13) and decreases in angiogenic and immunosuppressive factors (e.g., VEGFR-2, ANGPT1/2, CCL17), paralleling the systemic immune remodeling observed in preclinical models. Both baseline immune signatures and treatment-induced protein shifts were associated with clinical outcome. CONCLUSIONS: Cabozantinib promotes tumor immunogenicity through mitochondrial disruption and cGAS/STING activation, leading to immune remodeling in HCC. These findings provide mechanistic insight into the immunomodulatory effects of cabozantinib, support rational combinations with STING agonists, and highlight candidate biomarkers for predicting therapeutic response in TKI-treated patients.